Storage lesion of human platelets as revealed by ultrathin sections and freeze-fracture replicas

Membrane phase transition of intact human platelets: correlation with cold-induced activation

Using Fourier transform infrared spectroscopy (FTIR), we have determined the phase transition temperature (Tm) of lipids in intact human platelets and have shown that it occurs between 15 and 18 degrees C, the temperature at which cold activation of platelets has previously been reported (Zucker and Borrelli, 1954, Blood, 28:602-608; White and Krivit, 1967, Blood, 30:625-635). The temperature at which the platelets pass through Tm is highly correlated with initial platelet shape change. However, shape change continues after the cells have passed through the phase transition. Cold-induced activation has previously prevented long-term storage of platelets at 4 degrees C. Antifreeze glycoproteins (AFGPs) isolated from polar fishes previously have been used to prevent ice crystal growth during freezing of tissues as well as leakage of solutes from liposomes as they were chilled through their Tm. We sought to determine if these AFGPs were able to stabilize platelets for long-term storage at 4 degrees C. Incubating platelets with antifreeze glycoproteins during long-term storage and rapid rewarming to 37 degrees C abrogated granule secretion associated with cold activation in a dose-dependent manner. This work suggests that AFGPs may be a possible solute for use in long-term low temperature storage of platelets.

Platelets stored in a glucose-free additive solution or in autologous plasma--an ultrastructural and morphometric evaluation

We evaluated a new glucose-free citrate-acetate-NaCl platelet additive solution (PAS 2). In series I, platelet concentrates (PC) were prepared by apheresis and subsequently stored either in plasma (n = 16) or in PAS 2 (n = 15). In series II, PCs were prepared from pools of four buffy coats (BC) and stored in plasma (n = 12) or in PAS 2 (n = 11). By means of ultrastructural morphometry, the volume fractions of alpha-granules, the open canalicular system (OCS) and the fraction of storage granules secreted into the OCS were analyzed during storage for up to 8 days. Additionally, we determined pH, glucose, lactate, pCO2, HCO3-, lactate dehydrogenase and platelet factor 4. Apheresis platelets stored in plasma showed no changes in their contents of alpha-granules and in the fractions of the OCS. In contrast, apheresis platelets stored in PAS 2 displayed a decrease of their relative volume fraction of alpha-granules from 9.1 +/- 1% on day 1 to 3.7 +/- 0.9% on day 5. The fraction of the OCS increased from 7.4 +/- 0.8% on day 1 to 17.1 +/- 1.4% on day 3. On day 8, 93 +/- 9% of all platelets were lysed. Levels of glucose were significantly lower in these preparations and after day 3 glucose consumption decreased to zero. Among PC derived from pooled BC, differences between storage in PAS 2 or plasma were less striking. Only the fraction of alpha-granules secreted into the OCS was significantly greater in BC derived PC stored in PAS 2 on all days. These PCs stored in PAS 2 had a higher plasma carryover (30%) in comparison to apheresis PC stored in PAS 2 (10%). We conclude that plasma is superior to PAS 2 for storage of both apheresis and buffy coat platelets. For preservation of the structural integrity of platelets, the use of PAS 2 requires a minimum of 30% plasma carryover.